From f83d8a3b532097276266b5e81073ea46e27b17ab Mon Sep 17 00:00:00 2001 From: Yuezhang Mo Date: Thu, 7 Apr 2022 15:55:56 +0800 Subject: [PATCH] exfat: reduce the size of exfat_entry_set_cache In normal, there are 19 directory entries at most for a file or a directory. - A file directory entry - A stream extension directory entry - 1~17 file name directory entry So the directory entries are in 3 sectors at most, it is enough for struct exfat_entry_set_cache to pre-allocate 3 bh. This commit changes the size of struct exfat_entry_set_cache as: Before After 32-bit system 88 32 bytes 64-bit system 168 48 bytes Signed-off-by: Yuezhang Mo Reviewed-by: Andy Wu Reviewed-by: Aoyama Wataru Reviewed-by: Sungjong Seo Signed-off-by: Namjae Jeon --- fs/exfat/exfat_fs.h | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index a8f8eee..af55018 100644 --- a/fs/exfat/exfat_fs.h +++ b/fs/exfat/exfat_fs.h @@ -9,6 +9,7 @@ #include #include #include +#include #define EXFAT_ROOT_INO 1 @@ -41,6 +42,14 @@ enum { #define ES_2_ENTRIES 2 #define ES_ALL_ENTRIES 0 +#define ES_IDX_FILE 0 +#define ES_IDX_STREAM 1 +#define ES_IDX_FIRST_FILENAME 2 +#define EXFAT_FILENAME_ENTRY_NUM(name_len) \ + DIV_ROUND_UP(name_len, EXFAT_FILE_NAME_LEN) +#define ES_IDX_LAST_FILENAME(name_len) \ + (ES_IDX_FIRST_FILENAME + EXFAT_FILENAME_ENTRY_NUM(name_len) - 1) + #define DIR_DELETED 0xFFFF0321 /* type values */ @@ -68,9 +77,6 @@ enum { #define MAX_NAME_LENGTH 255 /* max len of file name excluding NULL */ #define MAX_VFSNAME_BUF_SIZE ((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE) -/* Enough size to hold 256 dentry (even 512 Byte sector) */ -#define DIR_CACHE_SIZE (256*sizeof(struct exfat_dentry)/512+1) - #define EXFAT_HINT_NONE -1 #define EXFAT_MIN_SUBDIR 2 @@ -125,6 +131,17 @@ enum { #define BITS_PER_BYTE_MASK 0x7 #define IGNORED_BITS_REMAINED(clu, clu_base) ((1 << ((clu) - (clu_base))) - 1) +#define ES_ENTRY_NUM(name_len) (ES_IDX_LAST_FILENAME(name_len) + 1) +/* 19 entries = 1 file entry + 1 stream entry + 17 filename entries */ +#define ES_MAX_ENTRY_NUM ES_ENTRY_NUM(MAX_NAME_LENGTH) + +/* + * 19 entries x 32 bytes/entry = 608 bytes. + * The 608 bytes are in 3 sectors at most (even 512 Byte sector). + */ +#define DIR_CACHE_SIZE \ + (DIV_ROUND_UP(EXFAT_DEN_TO_B(ES_MAX_ENTRY_NUM), SECTOR_SIZE) + 1) + struct exfat_dentry_namebuf { char *lfn; int lfnbuf_len; /* usually MAX_UNINAME_BUF_SIZE */ @@ -166,11 +183,11 @@ struct exfat_hint { struct exfat_entry_set_cache { struct super_block *sb; - bool modified; unsigned int start_off; int num_bh; struct buffer_head *bh[DIR_CACHE_SIZE]; unsigned int num_entries; + bool modified; }; struct exfat_dir_entry { -- 2.7.4